Chaeles



Patented Feb. 9, 1886.

NITED STATES PATENT OFFICE9 CHARLES C. DRAKE, OF TRENTON, NEW JERSEY.

TELEGRAPH AND TELEPHONE PROTECTOR.s

SECIFICATION forming part of Letters Patent No. 336,040, dated February9, 1886.

Application filed October 24,1883. Serial No. 109,929. (No model.)

have invented certain new and useful Improvements in Protectors forTelephonie and Telegraphic Instruments, of which the following is aspecification.

My invention relates to a device adapted to 1o be placed in circuit withtelephonic, telegraphic, or other similar instruments, and by means ofwhich they are protected from the injurious or destructive action ofelectric currents of greater potential or quantity than those with whichthey are designed to work,

and which normally traverse the circuits in which such instruments areincluded.

It is a matter of frequent occurrence in locations where conductorsconvey currents of 2c electricity having a considerable difference ofpotential or quantity, and where such conduct-ors arc arranged near toone another, that they may become, from various causes, entangled, or aconductor by becoming detached from its support may fall and so cross7the conductor or conductors of other circuits. Thus, for instance,conductors conveying heavy currents-such as are used for electriclighting systems-may in this manner be brought into 3o contact with theconductors conveying the relatively weak and feeble currents employedwith telegraphic or telephonie system, and the latter become media forconveying currents of abnormal intensity or quantity. Static charges mayalso during atmospheric electrical disturbances acccumulate on theconductors and be discharged with serious effect. Hence it is desirableto arrive at a means for diverting such excessive or abnormal currents4o from that portion of the main circuit in which the instrument orinstruments it is desired to protect are located. At the same time it isalso desirable that the instrument or instruments should be not cut outof circuit, but should always be in a condition to perform its or theirnormal functions irrespective of any excess of current above the normalamount circulating in the main line.

-To attain this object I have devised the 5o herein-described instrumentorprotecting device, which consists,essentially,of two electromagnets,one of which has its coil or coils formed from a few turns of coarsewire of low electrical resistance, and the other its coils formed from anumber of turns of fine wire of high electrical resistance; or but asingle core may be used and the helices of different resistances woundthereon and provided with an armature arranged between an adjustablecontact-point over the electro-magnets and an insulated adjustable backstop and adapted to be normally held away from its electromagnet bymeans of its own weight, or by a retractile spring, which can be soadjusted as to prevent the armature from responding to currentstraversing the magnet or magnets not exceeding the ordinaryworking-current.

The present application relates toa protecting device similar to thatdescribed in United States Letters Patent granted to me July 10, 1883,and numbered 280,916, the only difference being that I include atine-wire magnet, which shall act in conjunction with the coarsewiremagnet, and thus render the instrument more sensitivein its action. Asbefore stated, the coils on the electro-magnets are in the main-linecircuit, and hence any current which circulates in the main line mustnecessarily pass through the coils of the magnets. After passing throughthe magnets the circuit is divided into two parts or paths one of highresistance, within which is included the telegraphic, telephonie, orother instruments to be protected, and the other of low resistance,normally open, but adapted to be closed when the current circulating inthe main line imparts sufficient energy to the electro-magnet to enableit to attract its armature. It will be readily understood that thecurrents in the paths or branches will be in the inverse ratio of theirresistances, and hence, if the resistances be properly proportioned, acurrent which will be sufficient to enable the telegraphic, telephonie,or signaling instruments to perform their normal functions, but notsufficient to injure them, will at all times be transmitted through theinstruments, the strength or quantity of the current so transmittedvarying with that of the main line,and all excess of current will bediverted through the path of low resistance around the protectedinstruments to ground or back to the mainline conductor.

In the accompanying drawings,which illus- ICO trate my inventiomsi-milarlettersot--reference indicatelike parts.'

Figure 1 shows a view in perspective of a protector constructedaccording to my invention. Fig. 2 is a diagrammatic view illustrative oftheY different circuits and connections.

In the drawings, Arepresents the main-line conductor, connected to thebinding-post B. To the binding-post B, I attach one end of a coarsecopper wire, which is wound around' the core of the magnet C to form itscoil or coils, ending at the screw E, which passes through and securesthe conducting-uprightK to the base of the instrument; Attached` by oneend to the screw E is a fine copper wire, which is wound around the coreof the magnet O toform itscoil or coils, the'otherrend being carriedtofthe binding-post F. I prefer t wind4 the magnet C with butfew-convolutions ofA-acoarsecopper wire, whose electrical resistance forany given length shall befeqnaltoY or less-.than that of a similarlength of the main-line conductor.

rent; transmitted through the circuit will cause the magnettobecome'energized and attract the armature.

I do not-limit myselfv to theA particular arrangement ofl the magnets.The; fine. and coarsewire;helicesmaybewound on the same core,. orarranged in relative positionsother than that shown and. described.Locatedv in` front of the magnet, and support'ed'uponI an insulatedaXis, l, is the armature D,.the1end etw-hichprojects upward betweenl twosetscrews, S` G, arranged in the head offthe uprightK. The set-screwslare so arranged as: tobegvadjustable, andlto determine` Or'iimittheplayofthe armature. One of the set.-` screws, G, is provided with av tiprofinsulating material, which serves to insulate the arma ture, which iswholly of conducting material,

from the upright K,when the armature rests against .the set-screw, thatbeing its normal` position when uninfluenced bythe magnets. The lowerend of the armature, is connected through-the'copper wireYL-with-thebinding- 5o post M.

On the end of the instrument,arranged in a line :with the armature,is-asuitablesupport,` O, for the tension-screw P.'

I-Iisa tension-spring, connected at one vendto but insulated fromthearmatureD, and at tachedat the other end to the tensioni-screw P..

y Having thus described the invention so far asv relates to. itsmechanicaly construction, I

. cuit.

The amount offine wire used upon thefmagnet C shouldbe-sutcient. 25to=offer a resistanceto the passageoffthe nor-- mal current, so that anyslightincrease of cur--A tionwhen included in` the main-line circuityThe main-line conductorl A- isconout through, the vbinding-.post QF,andi thence byltl'rev conductor A to'thegbinding-post A2, by thetelephone-cord A3 to telephone T, by cord A? to binding-post A5, toreturn mainline conductor A6. It will be understood that the main-lineconductor A A. can bea closed metallic circuit, or the ends oftheconductors may be connected to ground. The path ofthe current asdescribed isv the path of the normal current, which is sufficient inamount to operate the instruments included in the cir- It isA obviousthat the conductors A and A6 can be connected directly to the instrumentor'instruments to be protected without the intervention of any cord,such as those at A3 and A. A current of* the amountvdescribedftraversing the normal,l circuit and-.the coil ofthefelectro-magnetor magnets :will not impart suiicient energy-toit orthem to at-` 85 tract thel'varmature, which is normally held awayfromithe magnets bythe tensionof` the" spring H. The tension ofrthisnspringcau be so adjusted as to exertvmorefor less pull upon thearmature, and thus providesfa means. of 9o regulating the`amount'ot'current ,which -can betransmittedthroughY the normal circuit.Should any abnormal current be thrown uponv the mai-n line'A, all ofsuch current willv pass: throughfthennagnets C andvG, instantlyenergizing them, soi asto attract the armature D and overcome thetension of the spring Hand bring the end ofthe armature in contact withthe adj ustable-'contact-point Son the :upright K. By making suchcontact-a path of lowA roo resistanceL-from binding-post B through themagnet-'C to screw E, by conducting upright;- K, screw' S, armature D,wireLto binding;-Y post M,.a nd thence by the conductor W to the;-return main'line'conductorAor to ground-#105 isprovided, and the currentwill divide andl circulate through the two paths, the amountl oi'-current transmitted through the vseparate paths .being inthe inverseratio of their ref sistances.- Should any-abnormal current.A be: I iothrownupon the return main-line conductor AQthefpath' of the currentwill first be through the telephone by vconductor A to the magnets,whieh'will attract the armature as before'and c lose'the path oflowresistance, the1pathoff..r15 the-current then beingdfrom Afbyconductor,A W tobinding-post IVI,- wire1L, armature- D, screwS. screw-E,magnet C tor-main conductor A,which'may be connected toy ground. It willbepnoticed' thatw-hen any abnormal current isiizo thrown upon theconductors A or Avandthe: armature attracted, thecurrent dividesjat the'screw E, and the magnet C is included inthe path of highk resistance.`

Irwishitunderstood that I do notlimitmyf' x2 5 self-to thelparticularrmechanical construction ofthe. device-showninfthegdrawingsand de:Ascribed ini thef specification, as it isV obvious. that many changes canbe madethereinrwithoutdepartin g from'theint'ent of vmy invention. x 3oIamaware. that-various devices have here;-l toforef-4 been? constructedfor.. automatically.

breaking the circuit or for cutting the instruments to be protected outof the circuit; but, so far as I am aware, I am the rst to construct adevice which will automatically divert abnormal currents to earth fromthe main circuit without breaking or otherwise interfering with thecircuits in which the instruments to be protected are located; or, inother words, a device located in the main circuit, and through which allthe currents circulating on the main circuit pass ,which is inactive andnon-responsive to the normal current,but instantly responsive to anabnormal current, whereby the current is split up or divided into twoparts and caused to travel two paths of unequal resistance.

I claim as my inventionl. The combination of an electric circuit andelectrical instruments included therein, through which a path of highresistance is always maintained, with an automatic electromagneticdevice consisting of high and low resistance magnets, and connectionsconstructed to automatically close a path of low resistance around saidinstruments when the current traversing the main line exceeds the normalamount.

2. The combination of an electric circuit and electrical instrumentsincluded therein with a pivoted armature, two electro-magnets, one ofhigh and the other of low resistance, both of which are in the main-linecircuit, and

the means controlled by the armature to divert through a path of lowresistance around the electrical instruments any excess of current abovethat normal to the line.

3. The combination of an electric circuit and electrical instrumentsincluded therein, through which a path of high resistance is alwaysmaintained,with an automatic electromagnetic device consisting ofamagnet having high and low resistance helices, and connections,substantially as described, constructed and connected to automaticallyclose a shuntcircuit of low resistance around the receivinginstrumentwhen the main line is overcharged, and mechanism, substantially as setforth, to retract the armature to its normal position when current inthe main line again becomes normal.

4. The combination, with an electric circuit and the electricalinstruments included therein, of the means whereby excessive currentsare divided and caused to traverse two paths of unequal resistance,consisting of two electro-magnets, one of high and the other of lowresistance,a pivoted armature and its connections, and a conductor oflow resistance connected to the return main-line conductor, substantially as described.

CHARLES C. BRAKE.

\Vitnesses:

JOHN A. STEEN, Lewis W. SCOTT.

